V6, V8, V10,V12,V16 ?

[FrustratedUser]

Originally posted by: Zenmervolt

Originally posted by: Howard

Originally posted by: FrustratedUser

Originally posted by: 91TTZ

Originally posted by: Howard
Really now. Do you think a 4L I6 would make the same power as a 4L V12?

Because the 4L V12 will make more power.

Yes, I do. And it will.

The 4L V12 will be smoother, but being a V12 in itself does not make it any more powerful.

You can't just say that.

Yes, I can. The V12 will be able to rev up higher than the I6 will. And assuming the intake/combustion chamber/exhaust geometry is good, specific torque output will remain about the same.

EDIT: Yes, assuming the bore/stroke ratio is the same. The V12 will have a cylinder displacement half that of the I6 - easier to breathe at high RPMs, especially since valve area will be almost the same as in the I6.

How on earth can the valve area be almost the same when each cylinder would have to be half the size? You'll lose a hell of a lot of valve area on the V12.

ZV

EDIT: The V12 will also have higher frictional losses, and will have more parasitic loss from the valvetrain.

Just set up th equations.
Fit 2 circles in a circle and calculate how many procent they can cover.
Now do the same thing for 4 circles. Report back...

 

[thomsbrain]

adding more cylinders is an easy way to increase displacement. simply making the cylinders bigger works, too, but as each piston gets bigger, it weighs more and can't rev as high without tearing the rest of the engine to bits. so if you use more small cylinders, you can get the same displacement while using wimpier bits. the downside is it probably takes a lot more engineering to get all those cylinders working together, and there's more stuff to break.

 

[Zenmervolt]

Originally posted by: FrustratedUser

Originally posted by: Zenmervolt

Originally posted by: Howard

Originally posted by: FrustratedUser

Originally posted by: 91TTZ

Originally posted by: Howard
Really now. Do you think a 4L I6 would make the same power as a 4L V12?

Because the 4L V12 will make more power.

Yes, I do. And it will.

The 4L V12 will be smoother, but being a V12 in itself does not make it any more powerful.

You can't just say that.

Yes, I can. The V12 will be able to rev up higher than the I6 will. And assuming the intake/combustion chamber/exhaust geometry is good, specific torque output will remain about the same.

EDIT: Yes, assuming the bore/stroke ratio is the same. The V12 will have a cylinder displacement half that of the I6 - easier to breathe at high RPMs, especially since valve area will be almost the same as in the I6.

How on earth can the valve area be almost the same when each cylinder would have to be half the size? You'll lose a hell of a lot of valve area on the V12.

ZV

EDIT: The V12 will also have higher frictional losses, and will have more parasitic loss from the valvetrain.

Just set up th equations.
Fit 2 circles in a circle and calculate how many procent they can cover.
Now do the same thing for 4 circles. Report back...

Both engines would have to have the same number of valves/cylinder or the comparison is not appropriate because it's introducing an additional variable that is not controlled for. You can't give one engine a valve setup optimized for maximum use of the available cylinder head space and not give that to the other engine or else it will invalidate the entire comparison.

In other words, if the valve area per cylinder of the I6 is 50%, then the valve area for the V12 must also be 50% or you end up testing the effect of valve area and NOT the effect of engine configuration.

ZV

 

[Howard]

I didn't do the math when I made that statement, so let me fix my error by doing it now.

Well, it looks like I was dead wrong. A bore/stroke ratio of approximately 1.11 means a bore of 78mm for the V12, and a bore of 98mm for the I6. My sincere apologies. However, even if the valve area is lower (much lower?) for the V12, it's not 50% less than the I6, I think (which still means a net increase in the ratio between valve area and cylinder displacement).

 

[FrustratedUser]

Originally posted by: Zenmervolt

Originally posted by: FrustratedUser

Originally posted by: Zenmervolt

Originally posted by: Howard

Originally posted by: FrustratedUser

Originally posted by: 91TTZ

Originally posted by: Howard
Really now. Do you think a 4L I6 would make the same power as a 4L V12?

Because the 4L V12 will make more power.

Yes, I do. And it will.

The 4L V12 will be smoother, but being a V12 in itself does not make it any more powerful.

You can't just say that.

Yes, I can. The V12 will be able to rev up higher than the I6 will. And assuming the intake/combustion chamber/exhaust geometry is good, specific torque output will remain about the same.

EDIT: Yes, assuming the bore/stroke ratio is the same. The V12 will have a cylinder displacement half that of the I6 - easier to breathe at high RPMs, especially since valve area will be almost the same as in the I6.

How on earth can the valve area be almost the same when each cylinder would have to be half the size? You'll lose a hell of a lot of valve area on the V12.

ZV

EDIT: The V12 will also have higher frictional losses, and will have more parasitic loss from the valvetrain.

Just set up th equations.
Fit 2 circles in a circle and calculate how many procent they can cover.
Now do the same thing for 4 circles. Report back...

Both engines would have to have the same number of valves/cylinder or the comparison is not appropriate because it's introducing an additional variable that is not controlled for. You can't give one engine a valve setup optimized for maximum use of the available cylinder head space and not give that to the other engine or else it will invalidate the entire comparison.

In other words, if the valve area per cylinder of the I6 is 50%, then the valve area for the V12 must also be 50% or you end up testing the effect of valve area and NOT the effect of engine configuration.

ZV

It's pure geometry. I did the math now. (Someone check me plz)

2 valves can fill maximum 50% of the area.
4 valves can cover 68.63% of the area.

It doesn't matter how big the bore is.
What's the additional variable you speak of?

 

[91TTZ]

Originally posted by: FrustratedUser

It's pure geometry. I did the math now. (Someone check me plz)

2 valves can fill maximum 50% of the area.
4 valves can cover 68.63% of the area.

It doesn't matter how big the bore is.
What's the additional variable you speak of?

It does matter how big the bore is, because the wider the bore, the larger the valves can be and the more air that those heads will flow. If you had a 3 liter engine, with a narrow bore and a long stroke, those heads won't flow nearly as well as a 3 liter with a wide bore and a short stroke. The valve area/bore area ratio wouldn't have changed, but the valve area will have increased significantly along with the bore area.

 

[EyeMWing]

Originally posted by: 91TTZ

Originally posted by: EyeMWing
[
To challenge the F1 would also be to challenge the reputation of one of the greatest designers that ever lived. He's not around anymore, so the F1 will remain the pillar of speed until someone with better ideas and vision comes along.

What do you mean by "he's not around anymore"?

I seem to recall that the lead designer is deceased and that his passing played a role in the decision to end production. Trying to Google it now, but a whole bunch of irrelevant stuff is coming up since McLaren is also involved in Formula 1.

Edit: Okay, I'll eat crow, Gordon Murray is not dead, he's still designing F1 cars. I hereby revise my above statements to "Nobody in Germany/Italy has the fvcking balls"

 

[91TTZ]

Originally posted by: EyeMWing
I seem to recall that the lead designer is deceased and that his passing played a role in the decision to end production. Trying to Google it now, but a whole bunch of irrelevant stuff is coming up since McLaren is also involved in Formula 1.

I thought the lead designer was Gordon Murray? He's still alive, he just left McLaren.

 

[Howard]

Originally posted by: FrustratedUser

Originally posted by: Zenmervolt

Originally posted by: FrustratedUser

Originally posted by: Zenmervolt

Originally posted by: Howard

Originally posted by: FrustratedUser

Originally posted by: 91TTZ

Originally posted by: Howard
Really now. Do you think a 4L I6 would make the same power as a 4L V12?

Because the 4L V12 will make more power.

Yes, I do. And it will.

The 4L V12 will be smoother, but being a V12 in itself does not make it any more powerful.

You can't just say that.

Yes, I can. The V12 will be able to rev up higher than the I6 will. And assuming the intake/combustion chamber/exhaust geometry is good, specific torque output will remain about the same.

EDIT: Yes, assuming the bore/stroke ratio is the same. The V12 will have a cylinder displacement half that of the I6 - easier to breathe at high RPMs, especially since valve area will be almost the same as in the I6.

How on earth can the valve area be almost the same when each cylinder would have to be half the size? You'll lose a hell of a lot of valve area on the V12.

ZV

EDIT: The V12 will also have higher frictional losses, and will have more parasitic loss from the valvetrain.

Just set up th equations.
Fit 2 circles in a circle and calculate how many procent they can cover.
Now do the same thing for 4 circles. Report back...

Both engines would have to have the same number of valves/cylinder or the comparison is not appropriate because it's introducing an additional variable that is not controlled for. You can't give one engine a valve setup optimized for maximum use of the available cylinder head space and not give that to the other engine or else it will invalidate the entire comparison.

In other words, if the valve area per cylinder of the I6 is 50%, then the valve area for the V12 must also be 50% or you end up testing the effect of valve area and NOT the effect of engine configuration.

ZV

It's pure geometry. I did the math now. (Someone check me plz)

2 valves can fill maximum 50% of the area.
4 valves can cover 68.63% of the area.

It doesn't matter how big the bore is.
What's the additional variable you speak of?

It's true that the percentage doesn't change, but the actual value does change if bore changes, which is what he's talking about. He caught me on my statement that valve area doesn't change too much.

 

[FrustratedUser]

Originally posted by: 91TTZ

Originally posted by: FrustratedUser

It's pure geometry. I did the math now. (Someone check me plz)

2 valves can fill maximum 50% of the area.
4 valves can cover 68.63% of the area.

It doesn't matter how big the bore is.
What's the additional variable you speak of?

It does matter how big the bore is, because the wider the bore, the larger the valves can be and the more air that those heads will flow. If you had a 3 liter engine, with a narrow bore and a long stroke, those heads won't flow nearly as well as a 3 liter with a wide bore and a short stroke. The valve area/bore area ratio wouldn't have changed, but the valve area will have increased significantly along with the bore area.

I am not sure who is answering what and when now.

 

[91TTZ]

Originally posted by: FrustratedUser

I am not sure who is answering what and when now.

Me neither. Just pick a comment and refute it

 

[FrustratedUser]

Did some more math:

Comparing valve area between a 3 liter V6 and a 3 liter V12 assuming bore/stroke ratio of the engines are identical. In this case a square ratio (1:1).

The V12 has 26% more valve area than the V6.

 

[raptor13]

You guys all (with a few exceptions and you know who you are) need to read this and figure out exactly what it is you're talking about. While you're waiting for that to be delivered, stop posting what you think you know and start posting facts. There. I said it.

<---- Taking graduate ICE classes at U of I.

 

[FrustratedUser]

Some more...

In order for the V6 in the previous example to have the same valve area as the 1:1 ratio V12. The V6 has to have a bore/stroke ratio of 1:1.4

Seeing this, we can clearly see the benefit of a V12 vs V6.
I think F1 engines run close to these ratios (correct me), imagine what ratio a V6 would have to be in F1 to get the same valve area :Q


So based on this and assuming bore/stroke ratios are reasonable and practically usable, I can say that theoretically a V12 will make more power than the V6.

 

[lobadobadingdong]

Originally posted by: DingDingDao

Originally posted by: Silversierra
I mean why not use a 4 cyl or 6 cyl with high displacement. I mean someone could make a 8.0 Liter 4 cylinder. Then because of size it would weigh less and fit in a smaller car. I know farm tractors are almost all 4 and 6 cylinder engines, 8 cyl is very rare. They just put big pistons in the 4 and 6 cyl. engines to get higher displacement.

:shocked:

Think about how big the cylinders would be, the pistons, rods, etc. etc. I think unless you could forge those parts out of something very, VERY strong, that engine would destroy itself very quickly.

not really, there are 8-litre 4 cyclinder deisel engines. Steel can take it quite well.

 

[Zenmervolt]

Originally posted by: FrustratedUser
Some more...

In order for the V6 in the previous example to have the same valve area as the 1:1 ratio V12. The V6 has to have a bore/stroke ratio of 1:1.4

Seeing this, we can clearly see the benefit of a V12 vs V6.
I think F1 engines run close to these ratios (correct me), imagine what ratio a V6 would have to be in F1 to get the same valve area :Q


So based on this and assuming bore/stroke ratios are reasonable and practically usable, I can say that theoretically a V12 will make more power than the V6.

You're right (kinda) since bore does not scale in direct proportion to displacement. The total vlave area is slightly larger. I was thinking of valve area per cylinder.

Of course, as I said earlier, this neglects the increased friction inherent to the V12.

ZV

 

[FrustratedUser]

Originally posted by: Zenmervolt

Originally posted by: FrustratedUser
Some more...

In order for the V6 in the previous example to have the same valve area as the 1:1 ratio V12. The V6 has to have a bore/stroke ratio of 1:1.4

Seeing this, we can clearly see the benefit of a V12 vs V6.
I think F1 engines run close to these ratios (correct me), imagine what ratio a V6 would have to be in F1 to get the same valve area :Q


So based on this and assuming bore/stroke ratios are reasonable and practically usable, I can say that theoretically a V12 will make more power than the V6.

You're right (kinda) since bore does not scale in direct proportion to displacement. The total vlave area is slightly larger. I was thinking of valve area per cylinder.

Of course, as I said earlier, this neglects the increased friction inherent to the V12.

ZV

We're barely skimming the surface on this subject.
Cheers ZV. :beer:

 

[Howard]

Originally posted by: FrustratedUser
Some more...

In order for the V6 in the previous example to have the same valve area as the 1:1 ratio V12. The V6 has to have a bore/stroke ratio of 1:1.4

Seeing this, we can clearly see the benefit of a V12 vs V6.
I think F1 engines run close to these ratios (correct me), imagine what ratio a V6 would have to be in F1 to get the same valve area :Q


So based on this and assuming bore/stroke ratios are reasonable and practically usable, I can say that theoretically a V12 will make more power than the V6.

Finally, vindicated.

:beer:

 

[FrustratedUser]

Originally posted by: Howard

Originally posted by: FrustratedUser
Some more...

In order for the V6 in the previous example to have the same valve area as the 1:1 ratio V12. The V6 has to have a bore/stroke ratio of 1:1.4

Seeing this, we can clearly see the benefit of a V12 vs V6.
I think F1 engines run close to these ratios (correct me), imagine what ratio a V6 would have to be in F1 to get the same valve area :Q


So based on this and assuming bore/stroke ratios are reasonable and practically usable, I can say that theoretically a V12 will make more power than the V6.

Finally, vindicated.

:beer:

I just like to add that I made a typo. It should be 'bore/stroke ratio of 1.4:1', not 1:1.4.

 

[91TTZ]

Originally posted by: FrustratedUser
Some more...

In order for the V6 in the previous example to have the same valve area as the 1:1 ratio V12. The V6 has to have a bore/stroke ratio of 1:1.4

Seeing this, we can clearly see the benefit of a V12 vs V6.
I think F1 engines run close to these ratios (correct me), imagine what ratio a V6 would have to be in F1 to get the same valve area :Q


So based on this and assuming bore/stroke ratios are reasonable and practically usable, I can say that theoretically a V12 will make more power than the V6.

For a Formula 1 car this is important. Approaching 19,000 rpm, they need every last ounce of airflow they can get. For a street car, on the other hand it's not. Street cars don't rev high enough for the top end airflow to make much of an impact. They need low end torque and a reasonable powerband. Chevy's LS series V8's with their pushrods have been holding their own for a while, so apparently the advantage of the high end airflow didn't benefit them enough to switch to DOHC.

Jaguar's V12's were never known as being high performance engines, they were just smooth.

I still maintain that on a normal engine, that you'd see on the street, being a V6 vs. V12 doesn't make much of a difference due to the above mentioned fact. Hell, pushrods only fell out of favor recently in the mainstream.

 

[boyRacer]

Originally posted by: EyeMWing

Originally posted by: 91TTZ

Originally posted by: EyeMWing
[
To challenge the F1 would also be to challenge the reputation of one of the greatest designers that ever lived. He's not around anymore, so the F1 will remain the pillar of speed until someone with better ideas and vision comes along.

What do you mean by "he's not around anymore"?

I seem to recall that the lead designer is deceased and that his passing played a role in the decision to end production. Trying to Google it now, but a whole bunch of irrelevant stuff is coming up since McLaren is also involved in Formula 1.

Edit: Okay, I'll eat crow, Gordon Murray is not dead, he's still designing F1 cars. I hereby revise my above statements to "Nobody in Germany/Italy has the fvcking balls"

Gordon Murray hasn't designed an Formula One car for over a decade now... McLaren's Formula One cars are designed by Adrian Newey. Murray's latest project though was the Mercedes SLR.

 

[Howard]

Originally posted by: 91TTZ

Originally posted by: FrustratedUser
Some more...

In order for the V6 in the previous example to have the same valve area as the 1:1 ratio V12. The V6 has to have a bore/stroke ratio of 1:1.4

Seeing this, we can clearly see the benefit of a V12 vs V6.
I think F1 engines run close to these ratios (correct me), imagine what ratio a V6 would have to be in F1 to get the same valve area :Q


So based on this and assuming bore/stroke ratios are reasonable and practically usable, I can say that theoretically a V12 will make more power than the V6.

For a Formula 1 car this is important. Approaching 19,000 rpm, they need every last ounce of airflow they can get. For a street car, on the other hand it's not. Street cars don't rev high enough for the top end airflow to make much of an impact. They need low end torque and a reasonable powerband. Chevy's LS series V8's with their pushrods have been holding their own for a while, so apparently the advantage of the high end airflow didn't benefit them enough to switch to DOHC.

Jaguar's V12's were never known as being high performance engines, they were just smooth.

I still maintain that on a normal engine, that you'd see on the street, being a V6 vs. V12 doesn't make much of a difference due to the above mentioned fact. Hell, pushrods only fell out of favor recently in the mainstream.

I don't recall talking about engines for street applications. Why talk about power in the general sense when it's not every last bit you can squeeze out?

 

[Demon-Xanth]

Originally posted by: FrustratedUser
It's pure geometry. I did the math now. (Someone check me plz)

2 valves can fill maximum 50% of the area.
4 valves can cover 68.63% of the area.

It doesn't matter how big the bore is.
What's the additional variable you speak of?

You are assuming that the valves are the same size. It's not uncommon at all to have a larger intake valve compared to an exhaust.

Example:
http://www.chevy350engines.com/ce12.html
This is a run of the mill, cheap as hell, made for a truck engine. Nothing on it is special in the least. Notice that the intake is 1.94" and the exhaust is 1.50".

Here is an idea of what the heads look like:
http://store.summitracing.com/largeimage.asp?part=EDL-60739
These have 2.02" intake and 1.60" exhaust valves.

Compare those pictures to this one of a Honda 1.8L engine's head:
http://hondatuningmagazine.com/tech/0307ht_crxproject21_z.jpg

One thing you may notice, is the difference in the size of those two heads. Even though the first head is for an engine more than three times the displacement, the head is actually smaller. This is what causes the size of many DOHC engines to be quite large, and heavy, given thier displacement when compared to thier pushrod competitors.

 

[Triumph]

Originally posted by: EyeMWing

Originally posted by: 91TTZ

Originally posted by: EyeMWing
[
To challenge the F1 would also be to challenge the reputation of one of the greatest designers that ever lived. He's not around anymore, so the F1 will remain the pillar of speed until someone with better ideas and vision comes along.

What do you mean by "he's not around anymore"?

I seem to recall that the lead designer is deceased and that his passing played a role in the decision to end production. Trying to Google it now, but a whole bunch of irrelevant stuff is coming up since McLaren is also involved in Formula 1.

Edit: Okay, I'll eat crow, Gordon Murray is not dead, he's still designing F1 cars. I hereby revise my above statements to "Nobody in Germany/Italy has the fvcking balls"

The Bugatti Veyron is supposed to top the McLaren F1's top speed record, but I say, who really cares? Top speed is for bragging rights, its pretty easy to make a car go fast in a straight line (relatively speaking), it's much harder to develop a well rounded package that does everything right. That being said though, the McLaren F1 was that well rounded package that did everything right.

 

[Triumph]

Ford 4.6L vs. 5.0L. A perfect example of the stupidity of marketing sometimes. OHC is better than pushrods!